In a biological science field, there is an analytical method of concurrently detecting a minute luminescence process for a large number of samples. For example, when wishing to fix proteins included in a solution, an ELISA method (Enzyme Linked Immuno Sorbent Assay method) or the like has been used from the past. The ELISA method is a measurement method involving immersing a substrate on which a large number of antibodies are arranged/fixed into a solution including proteins as a measurement target, exposing it to antibodies that have undergone fluorescence modification after that, and exposing it to excitation light to observe it with a microscope. With such a method, which antibody reacted with respect to what fluorescence position can be judged.
On the other hand, most of the light generated in the luminescence process starting with fluorescent light is radiated isotropically in a peripheral space. Therefore, in the method that uses a microscope for observing a luminescence process as in the ELISA method or the like described above, there is a problem that detection efficiency is limited due to light collection efficiency of a microscope, and thus a favorable result cannot be obtained.
As a method of improving the detection efficiency in a luminescence process, a light-receiving device may be provided in the vicinity of a luminescence source (sample). For example, if a luminescence process of a detection target is caused in a fairly-small space, a CMOS (Complementary Metal Oxide Semiconductor) or CCD (Charge Coupled Device) image sensor can be used.
In this case, by structuring a light detection system in a form in which a unit pixel of an image sensor corresponds to one luminescence process, luminescence processes of a million unit can concurrently be recorded and analyzed in time series. Moreover, with a structure in which the luminescence processes appear in the vicinity of a surface of the image sensor, the concurrent luminescence processes of a large number of samples can be measured with a compact detection system.
From the reasons as described above, there is proposed an image sensor for measuring body tissues such as a cell (see, for example, Patent Documents 1 and 2). For example, in the image sensor disclosed in Patent Document 1, for improving detection accuracy, an optical filter layer that transmits a fluorescence wavelength range as well as block an excitation light wavelength range is provided on an upper surface of a photodiode of each pixel cell.
On the other hand, in the image sensor disclosed in Patent Document 2, a detection sensitivity is improved by forming an antireflection film on a light-receiving surface and improving a transmission on the light-receiving surface. Moreover, in the image sensor disclosed in Patent Document 2, a spot where a large number of biological macromolecules such as a single-strand probe DNA are gathered is formed in a matrix on the antireflection film, and a specific sample is coupled to the spot.